1.事务:保证一个多操作的事情全部完成,否则回到做之前的状态
begin try
begin tran–设置反悔点,开启事务
delete from UserInfo where UserId>5
delete from ClassInfo
commit tran–不反悔,提交事务
end try
begin catch
rollback tran–反悔啦,回滚事务
end catch
2.锁:防止其它人员的误操作，加了锁只有自己可以执行这个操作
select * from UserInfo
begin tran–加锁
update UserInfo set UserName=‘abc1’ where UserId=10
rollback tran–开锁
3.存储过程
create proc trim
@str1 varchar(10)
as
begin
select LTRIM(RTRIM(@str1))
end
–‘abc’
exec trim ’ abc ’
create proc GetPage
@pageIndex int,
@pageSize int,
@rowsCount int output
as
begin
SET NOCOUNT ON;
select @rowsCount=COUNT() from StudentInfo
select * from
(select ,ROW_NUMBER() over(order by sid desc) as rowIndex
from StudentInfo) as t1
where rowindex between (@pageIndex-1)@pageSize+1 and @pageIndex@pageSize
end
declare @temp int
exec GetPage 1,2,@temp output
print @temp
4.索引
select * into test2 from PersonList
select * into test1 from PersonList
create nonclustered index ix_phone
on test1(pPhone)
set statistics time on
select * from test1
select * from test1–CPU 时间 = 0 毫秒，占用时间 = 0 毫秒。
where pName=‘王美霞’
select * from test2-- CPU 时间 = 15 毫秒，占用时间 = 20 毫秒。
where pName=‘王美霞’
5.触发器
select * into classTest from ClassInfo where 1=2
select * from ClassInfo
select * from classTest
create trigger ClassInfo_Delete on ClassInfo
after delete
as
begin
set nocount on
insert into classTest(ctitle)
select ctitle from deleted
end
delete from ClassInfo where cId=4